Clamp pad for roll clamping mechanism



Aug. 3, 1965 K. H. MINDRUM CLAMP PAD FOR ROLL CLAMPING MECHANISM 4 Sheets-Sheet 1 Filed Deo. 27. 1961 Aug- 3, 1965 K. H. MINDRUM 3,198,568

CLAMP PAD FOR ROLL CLAMPING MECHANISM Filed Dec. 27. 1961 4 Sheets-Sheet 2 Aug. 3, 1965 K. H. MINDRUM CLAMP PAD FOR ROLL CLAMPING MECHANISM 4 Sheets-Sheet 5 Filed Dec. 27, 1961 Aug- 3, 1965 K. H. MINDRUM 3,198,568

CLAMP PAD FOR ROLL GLAMPING MEGHANISM Filed Dec. 27, 1961 4 Sheets-Sheet 4 Y INVENTOR.

United States Patent O 3,l98,563 CLAMP RPA@ RLL CLAD/@ENG MEQHANESM Kenneth H. lviindrum, Battle Creek, Mich., assigner to @lar-h Equipment Company, a corporation of Michigan Filed Deci 27, wel, Ser. No. 162,339 Claims. (QL 29d-33) The present invention relates to a clamping device having a pair of opposed clamping arms adapted to be moved towards and away from one another by hydraulic actuating means, and adapted to be mounted as an elevatable attachment on the lifting mast of an industrial lift truck for transporting and stacking cylindrical objects of widely varying diameters, such as paper rolls and the like.

More specicall the invention relates to a device of the character mentioned wherein each of the clamping arms has -a corresponding clamp pad pivotally mounted at its outer end whereby upon movement of said arms towards one another a load may be squeezed between the two clamp pads and securely held thereby.

Previously proposed clamping mechanisms embody clamp pads which are pivotally mounted at the ends ofthe clamping arms to grip a load therebetween. Such known devices commonly embody clamp pads which are freely pivotable, although in such cases uncontrolled swinging of the pads against the clamping arms when the latter are in motion produces undesirable noise, and also results in the clamp pads being randomly positioned when approaching a load, According to another known embodiment, hinge means is provided for mounting a clamp pad, and a coiled spring is provided for biasing each pad in a given direction.

One object of the present invention is to provide a clamp pad which is prevented from swinging freely when not under load by a hinge rod which co-operates therewith both to pivotally mount the pad on a clamping arm, and also to bias the pad to a predetermined optimum position for approaching a load.

Another object or the invention is to provide positive restraining means which limit the angle through which a pad may be rotated when subjected to clamping forces which cause it to be pivoted from its normal position.

In furtherance of the foregoing objects, l mount a clamp pad at the outer end of a clamping arm by means of a hinge rod which is secured at one end to the pad, and at its other end to a lined hinge on the arm, whereby the hinge rod functions not only to pivotally mount the pad, but also to yieldingly hold the pad in a given position. The hinge rod is secured at opposite ends to the pad and to the clamping arm so as to bias the pad to an intermediate pivotal position suitable for approaching a load, and upon engagement with a load the pad is pivotable in either direction aaginst the torsional resistance of the hinge rod to adjust to the outer configuration of the load. Pivoting oi the pad under load will twist the hinge rod, whereby upon release of the load the pad will be returned to its normal intermediate position.

ln order to limit the amount by which a clamp pad can be pivoted yunder load, l further provide restraining members or straps which are hinged to the pads at one end and have their opposite ends slidably guided in guides or tracks which are embodied in the clamping arm associated therewith to limit the movement of the straps.

The above and other objects will appear from the following detailed description of a preferred embodiment of the invention.

Now in order to acquaint those skilled in the art with the manner of utilizing and practicing my invention, l'

shall describe in conjunction with the accompanying drawings a preferred embodiment thereof.

In the drawings: l

FIGURE l is a perspective View showing the lifting mast of an industrial litt truck having mounted thereon a clamping mechanism embodying clamp pads'constructed and mounted in accordance with the present invention, the pads being shown in an intermediate pivotal position suitable for approaching a load;

FIGURE 2 is a fragmentary and somewhat schematic view showing yin solid lines a pair of clamping arms in extended positions for gripping a large diameter roll, the pads thereon being shown in their innermost or closed pivotal positions as when clamping a large diameter roll, and further showing in dash lines the clamping arms in their inner positions with the pads in their extreme outermost or open pivotal positions as when gripping a small diameter roll, th pads in the latter instance being shown pivoted outwardly to the full extent permitted by restraining members associated therewith; f

FlGURE 3 is an enlarged fragmentary elevational view showing the manner in which a clamp pad is mounted on the end of a clamping arm by a hinge rod secured at one 'end to the pad and at its other end to the arm, and further showing the restraining straps for limiting outward pivotal movement of the pad;

FIGURE 4 is an exploded perspective view of a clamp pad and 'a clamping arm on which it is adapted to be mounted; and

FEGURE 5 is an exploded perspective view of a clamp pad and clamping arm, illustrating in particular guide means carried by the arm tor limiting the movement of corresponding restraininU straps.

Referring now to the draty ings, FIGURE l shows a lifting mast 2d of an industrial litt truck. The lifting mast includes an elevatable cross beam Z2 on which a clamping mechanism, indicated generally at 2d, is mounted. The clamping mechanism comprises a pair of opposed clamping arms and 2d which are supported from a clamp base assembly 3@ for reciprocation towards and away from one another. The base assembly Titi may embody a pair of double acting hydraulic cylinders (not shown) for eil'ecting the reciprocation of the clamping arms. In addition, the clamp base assembly lill may be rotatably mounted with respect to a iixed base 32, and the latter may include a pair ot double acting cylinders such as shown at 34 for effecting rotation of the clamping mechanisrn about a horizontal axis. A clamping mechanism with which the clamp pad of the present invention may be used advantageously is fully described in a copending application, tiled by Elmer G. Bjorklund and Louis A. Haddock, Ir., Serial No. 166,983, filed December 21, i961, now Patent No. 3,l8ll,672, dated April 27, 1965, and assigned to the assignee or" the present invention.

A clamp pad 36 is mounted on the end of Vthe clamping arm 26 by a hinge rod 3S, the outward pivotal movement or opening oi the pad relative to the arm being limited by a pair of restaining straps 4th and 42 which are hinged to the pad at lugs id and 45, respectively, and extend through openings ttl and Sil in a front plate 52 on the arm 2d. ln a similar manner, a clamp pad 5d is mounted on the end of the clamping arm 23 by a hinge rod Se, and a pair of restraining straps S8 and @il are'hinged to the pad at lugs o2 and 64 and extend through openings 66 and 6?; in a iront plate 7@ on the arm 2S,

The inner ends of the restraining straps on each of the clamp pads are slidably engaged in guides or tracks embodied within the respective clamping arms, the straps being thereby limited in their movement so as to limit the pivotal movement of the pads. The pads 36 and 54 are shown in FGURE l in their normal intermediate pivotal positions in which they are yieldingly held by q) the torsion hinge rods 38 and 56, as will be described more fully hereinafter.

As shown in FIGURE 4, the clamp pad 36 is provided at its opposite ends with lugs 72 and 74, and an intermediate lug 76, each of which is apertured to receive the hinge rod 38. The arm 26 is provided withtwo extended tubular lugs or hinge portions 78 and 80 which are spaced apart sufficiently to permit the clamp pad lug 76 to be aligned therebetween. The pad 36 is` adaptedto be asn sembled to the clamping arm 26 with the lugs 72 and 74 positioned immediately outwardly of the outer ends of the lugs or hinge portions '78 and Si), respectively, and with the clamp pad lug 76 disposed between the inner ends of the lugs 78 and 80. The apertures in the various lugs or hinge members are aligned with one another, and the rod 38 is inserted therein to effect the desired hinged connection. FIGURE 4 further shows lugs or hinge members 44 and 46 on the pad 36 for connecting the restraining straps 40 and 42, respectively.

FIGURE 3 illustrates the assembly of the pad 36 on the arm 26, and it is an important feature of the invention that the hinge rod 38 is pinned or otherwise connected at one end to the pad, and at its other end to the arm, so as to act as a torsion member and yieldingly hold the pad in an intermediate pivotal position as shown in FIG- URE 1. In the illustrative embodiment disclosed a pin 82 is inserted through a small aperture in the clamp pad lug 72 and into a corresponding aperture in the end of the hinge rod 38, so as to fix one end of the rod to the clamp pad. Adjacent the opposite end of the rod 38, a similar pin 84 is inserted through a small aperture proxi mate the outer end of the clamping arm lug or hinge member 80, and into a corresponding aperture in the rod, so as to fix the latter rod end to the clamping arm. It will now be understood that the hinge rod 38 serves to pivotally mount the pad 36 on the clamping arm 26, and also acts as a torsion member to yielding maintain the pad in an intermediate pivotal position, the pad being movable from said position when subjected to clamping `forces suiiicient to twist the hinge rod. The pposing clamp pad 54 is mounted on the end of the arm 28 by the hinge rod 46 substantially in the manner described above with respect to the pad 36 and clamping arm 26.

Referring now to FIGURES 2 and 3, it will be seen that the restraining strap 40 is hinged at one end to the clamp pad 36 by a hinge pin 86 which extends through the lugs 44 on the pad and through an aperture in the end of the strap. The opposite end of the strap 40 is provided with an integral transverse guide rod 38, the

ends of which extend beneath respective guides 90 and -Y 92 which are welded or otherwise secured to a clamping arm back plate 94. Similarly, the strap 42 has one end hinged to the pad 36 by a hinge pin 96 which passes through lugs 46 on the pad and through an aperture in one end of the strap, the opposite end of the strap 42 having an integral transverse guide rod 98, the outer ends of which project beneath respective guide members 100 and 102. The openings 48 and 5i) in the front plate 52 which permit the restraining straps 40 and 42 to extend into the interior portion of the clamping arm 26 are illustrated in FIGURE 1.

As shown in FIGURES, the restraining strap `58 has one end hinged to the clamp pad 54 by a pin 194 which passes through hinge lugs 62 on the pad and through an aperture in the end of the strap. The strap 58 has a 70 which permit the restraining members 53 and 6i) to extend into the interior of the clamping arm 28.

It will be understood that while the guides 163 and 110 mounted within the arm 28 differ structually from the guidesl 99 and 92 carried by the arm 26, they serve substantially the same purpose as the latter, i.e to limit the movement of restraining straps associated therewith. The clamp pad 36 can be opened or pivoted outwardly during a clamping operation to the position shown in dash lines in FIGURE 2, whereupon the guide rods 88 and 98 will engage the ends of the guides or tracks associated therewith and further outward pivotal movement of the pad 36 will he prevented. In a similar manner, the clamp pad 54 can be opened or pivoted outtransverse guide rod 106 integral with its opposite end shown) substantiallyv identical to the guides 108 and 110.`

FIGURE 1 shows openings 66 and 63 in the front plate wardly to the position shown in dash lines, at which time the guide rod 106 will engage the ends of the guides 108 and 110 (as shown in FIGURE 5) preventing further outward swinging of the pad. The clamping arms 26 and 28 will serve as stops to limit the inward swinging of the pads.

In operation, with the clamping arms 26 and 28 extended, the clamp pads 36 and 54 are held in their intermediate pivotal positions by the respective hinge rods 3S and 56, and are thus yieldingly maintained in optimum positions to approach a load. If a large diameter load is to be clamped, such as the paper roll indicated at R in FIGURE 2, the arms are moved towards one another to squeeze the roll between the pads. The pads will thereupon be pivoted inwardly to the extent necessary to align with the configuration of the roll. The pivotal movement of the clamp pads is effected by the clamping forces developed between the roll and the pads, such forces causing twisting of the hinge rods 38 and 56. When the roll R is subsequently released, the clamp pads will be returned by the hinge rods to their intermediate pivotal positions.

When a small diameter load is to be clamped, such as the paper roll shown at R', the pivotal movement of the clamp pads, as they tend to align with the contour of the roll, will be outwardly. However, the restraining members 40, 42, 5S and 69 serve to positively limit the amount by which the respective pads may be swung outwardly when engaging a small diameter roll, and in the embodiment described yherein such limiting positions are substantially as shown in dash lines in FIGURE 2.

It will be understood that various modifications and rearrangements may be made in the embodiments selected for disclosing my invention without departing from the spirit and scope of the invention.

I claim:

1. In a clamping mechanism of the type having a pair of opposed clamping arms adapted to reciprocate towards and away from one another for handling paper rolls and the like, the improvement comprising, in combination, a clamping arm having first hinge means at the outer end thereof, a clamp pad having second complementary hinge means thereon in alignment with said first hinge means, a single member comprising a hinge rod and torsion spring arranged to project through said aligned first and second hinge means in operative engagement therewith to pivotally mount said pad on said clamping arm, rst connecting means at a iirst position along the length of said member for securing said member to said iirst hinge means t0 prevent relative rotation therebetween, and second connecting means at a second position spaced along the length of said member from said first position for securing said member to .said second hinge means to prevent relative rotation therebetween, whereby in addition to pivotally mounting said pad, said member will act as a torsion spring to yieldingly maintain said pad in a predetermined pivotal position relative to said clamping arm.

2. In .a clamping mechanism of the type having a pair of opposed clamping arms adapted to reciprocate towards and away from one another for handling paper rolls and the like, the improvement comprising, in combination, a

clamping arm having lirst hinge means at the outer end thereof, a clamp pad having second complementary hinge rmeans thereon in alignment with said first hinge means, a ysingle member comprising a hinge rod and ,torsion spring arranged to project thr-ough said aligned first and second hinge means in operative engagement therewith to pivotally mount said pad on said clamping arm, iirst connecting means proximate one end of said member for securing said member to said iirst hinge means to prevent relative rotation therebetween, and second connecting means proximate the other end of said member for securing said member to said second hinge means to prevent relative rotation therebetween, whereby in addition to pivotally mounting said pad, said member will act as a torsion spring to yieldingly maintain said pad in a predetermined pivot-al position relative to `said clamping arm.

3. In a clamping mechanism of the type having a pair of opposed clamping arms adapted to reciprocate towards and away from one .another for handling paper rolls and the like, the improvement comprising, in combination, a ciamping .arm having rst hinge means at the outer end thereof, a clamp pad having secondk complementary hinge means thereon in alignment with .said first hinge means, a single member comprising a hinge `rod `and torsion spring arranged to project through said aligned iirst and second hinge means in operative engagement therewith to mount said pad on said clamping arm for pivotal movement inwardly Iand outwardly relative thereto, irst connecting means proximate one end of said member for securing said member to said iirst hinge means .to prevent relative rotation therebetween, and second connecting means proX- imate the other end of said member for securing said member to said second hinge means to prevent relative rotation therebetween, said rst and second connecting means securing the first and second hinge means to the member in such .a manner as to y-ieldingly maintain the pad in an intermediate pivotal position in substantially unstressed condition of the member.

4. ln a clamping mechanism of the type having a pair of opposed clamping arms adapted to reciprocate towards and away .from one another for handling paper rolls and y the like, the improvement comprising, in combination, a clamping arm having tirst hinge means at the outer end thereof, a clamp pad having second complementary hinge means thereon in alignment with said rst hinge means, a single member comprising a hinge rod .and torsion spring arranged to project through said aligned first and second hinge means in operative engagement therewith to pivotally mount said pad on said clamping arm, irst connecting means at a iirst position along the length of said member for securing said member to said iirst hinge means t0 prevent relative rotation therebetween, second connecting member from said first position for securing said member means at a second position spaced along the length of said on said clamping arm, and a restraining member having one end hinged to said pad and its other end associated with said guide means for limited movement with respect thereto `to correspondingly limit the pivotal movement of said pad relative to said clamping arm.

S. In a clamping mechanism of the type having a pair of opposed clamping `arms adapted t-o reciprocate towards Iand away from one another for handling paper rolls and the like, the improvement comprising, in combination, a clamping arm having iirst `hinge means at the outer end thereof, `a clamp pad having second complementary hinge eans thereon in align-ment with said first hinge means, a

hinge rod arranged to project through said aligned iirst and second hinge. means in operative engagement therewith to pivotally mount said pad on said clamping arm, tir-st connecting means at a first position along the length of said hinge rod for securing said rod to said iirst hinge me-ans to prevent relative rotation therebetween, second connecting means at a second position spaced along the length of said hinge rod from said rst position for securing said r-od'to lsaid second hinge means to prevent relative rotation therebetween, whereby in addition t0 pivot-ally mounting said pad, said hinge rod will act as a torsion spring to yieldingly maintain said pad in a predetermined pivotal position relative to said clamping arm, a pair of guide members carried on said clamping arm, .and ya restraining member having one end hinged to said pad and having an integral transverse guide pin on itS other end, the end portions of said pin being adapted to cooperate wit-h said pair of guide members respectively for limited sliding .movement with respect thereto to correspondingly lim-it the pivotal movement of said pad relative to said clamping .arm when said pad is subjected to a clamping load tending to open said pad.

References Cited by the Examiner UNITED STATES PATENTS `1,717,194 6/29 Daoust.

2,635,774 y4/53 Backoiien et al 214-653 2,821,316 1/58 Saint 294-88 X 3,022,536 =2/62 Floehr 267-57 3,034,820 5/ 62 Schwartz 294-104 X 3,127,269 3/64 Faust 294-88 ROBERT B. REEVES, Acting Primary Examiner.

JAMES S. SHANK, ANDRES H. NIELSEN, LOUIS J.

DEMBO, Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,198,568 August 3, 1965 Kenneth H. Mndrum Column 5, line 53, strike out "member from said first position for securing said member" and insert the same after "said" in line 54, same Column 5.

Signed and sealed this 22nd day of March 1966.

(SEAL) Attest:

ERNEST W. SW'IDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

1. IN A CLAMPING MECHANISM OF THE TYPE HAVING A PAIR OF OPPOSED CLAMPING ARMS ADAPTED TO RECIPROCATE TOWARDS AND AWAY FROM ONE ANOTHER FOR HANDLING PAPER ROLLS AND THE LIKE, THE IMPROVEMENT COMPRISING, IN COMBINATION, A CLAMPING ARM HAVING FIRST HINGE MEANS AT THE OTHER END THEREOF, A CLAMP PAD HAVING SECOND COMPLEMENTARY HINGE MEANS THEREON IN ALIGNMENT WITH SAID FIRST HINGE MEANS, A SINGLE MEMBER COMPRISING A HINGE ROD AND TORSION SPRING ARRANGED TO PROJECT THROUGH SAID ALIGNED FIRST AND SECOND HINGE MEANS IN OPERATIVE ENGAGEMENT THEREWITH TO PIVOTALLY MOUNT SAID PAD ON SAID CLMAPING ARM, FIRST CONNECTING MEANS AT A FIRST POSITION ALONG THE LENGTH OF SAID MEM- 